Re: [PATCHv6 2/2] sched/deadline: Walk up cpuset hierarchy to decide root domain when hot-unplug

[kernel test robot <lkp@intel.com>]

Hi Pingfan,

kernel test robot noticed the following build errors:

[auto build test ERROR on tj-cgroup/for-next]
[also build test ERROR on tip/sched/core peterz-queue/sched/core linus/master v6.18-rc6 next-20251114]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Pingfan-Liu/cgroup-cpuset-Introduce-cpuset_cpus_allowed_locked/20251117-173841
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-next
patch link:    https://lore.kernel.org/r/20251117092732.16419-3-piliu%40redhat.com
patch subject: [PATCHv6 2/2] sched/deadline: Walk up cpuset hierarchy to decide root domain when hot-unplug
config: x86_64-allnoconfig (https://download.01.org/0day-ci/archive/20251117/202511171845.tuNk3Eb6-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251117/202511171845.tuNk3Eb6-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511171845.tuNk3Eb6-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from kernel/sched/build_policy.c:58:
>> kernel/sched/deadline.c:2937:2: error: call to undeclared function 'cpuset_cpus_allowed_locked'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    2937 |         cpuset_cpus_allowed_locked(p, cpus);
         |         ^
   1 error generated.


vim +/cpuset_cpus_allowed_locked +2937 kernel/sched/deadline.c

  2910	
  2911	/*
  2912	 * This function always returns a non-empty bitmap in @cpus. This is because
  2913	 * if a root domain has reserved bandwidth for DL tasks, the DL bandwidth
  2914	 * check will prevent CPU hotplug from deactivating all CPUs in that domain.
  2915	 */
  2916	static void dl_get_task_effective_cpus(struct task_struct *p, struct cpumask *cpus)
  2917	{
  2918		const struct cpumask *hk_msk;
  2919	
  2920		hk_msk = housekeeping_cpumask(HK_TYPE_DOMAIN);
  2921		if (housekeeping_enabled(HK_TYPE_DOMAIN)) {
  2922			if (!cpumask_intersects(p->cpus_ptr, hk_msk)) {
  2923				/*
  2924				 * CPUs isolated by isolcpu="domain" always belong to
  2925				 * def_root_domain.
  2926				 */
  2927				cpumask_andnot(cpus, cpu_active_mask, hk_msk);
  2928				return;
  2929			}
  2930		}
  2931	
  2932		/*
  2933		 * If a root domain holds a DL task, it must have active CPUs. So
  2934		 * active CPUs can always be found by walking up the task's cpuset
  2935		 * hierarchy up to the partition root.
  2936		 */
> 2937		cpuset_cpus_allowed_locked(p, cpus);
  2938	}
  2939	

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